Journal: Pneumonia
Article Title: Fluorescent antibody-based detection and ultrastructural analysis of Streptococcus pneumoniae in human sputum
doi: 10.1186/s41479-025-00157-z
Figure Lengend Snippet: In vitro and in vivo detection of pneumococci with fluorescently-labelled antibodies. Strain TIGR4 ( A ) was mixed with anti S4-A488 (green) antibody and observed under a epifluorescence microscope within five minutes. ( B ) Spn serotype 19F strain 4924 was cultured for four h in a 8-well slide and pneumococci attached to the substratum were stained with an anti S19-A555 (red) antibody and the DNA was stained with DAPI. ( C - D ) Human pharyngeal cells grown to confluence were inoculated with ( C ) strain D39 or ( D ) a mixture of strain D39 and strain TIGR4 and incubated for four hours. D39 was stained with S2-A555 (red) and TIGR4 was stained with S4-A488. In panel C, DNA was stained with TO-PRO-3, while in panel D, it was stained with DAPI. ( E - F ) C57BL/6 mice ( N = 11) were intranasally inoculated with serotype 19F strain EF3030. After 48 h, mice were euthanized, and the nasal bone was removed. Nasopharyngeal tissue was collected, sectioned (∼5 μm), or homogenized. Nasopharyngeal homogenate ( E ) or tissue sections ( F ) were stained with DAPI and with an anti S19-A555 antibody. Arrows point out Spn. In panels B-F, micrographs were obtained by confocal microscopy, and the projection of z-stacks is shown. ( G ) Nasopharyngeal homogenates were diluted and plated to obtain the bacterial density. The density in the plot was grouped according to whether the samples yielded a positive reaction with Spn-FLUO or were not detected (ND). Student t test, ** p = 0.01
Article Snippet: Confocal micrographs were obtained using a Nikon C2 laser scanning confocal microscopy system and analyzed using the Imaris software (Bitplane).
Techniques: In Vitro, In Vivo, Microscopy, Cell Culture, Staining, Incubation, Confocal Microscopy